This invention relates to the use of polyether hydroxycarboxylate copolymers in textile manufacturing and treating processes. The copolymers help stabilize bleach and reduce scale, prevent redeposition of particulate soils, prevent deposition of metals, and disperse dyes.
Heavy metal ions and salts deleteriously effect the desizing, scouring, bleaching, mercerising, and dyeing processes of textiles. For example, in the bleaching process, bleaching by hydrogen peroxide is generally carried out under an alkaline condition of a pH value of 10 to 14, and the reaction effectively improving the whiteness is represented by the formula: H2O2xe2x86x92HOxe2x88x922+H+, the active bleaching component is the perhydroxyl ion. However, under alkaline conditions (pH of at least 10), the side reaction represented by the formula: 2H2O2xe2x86x922H2O+O2 is promoted by heavy metal ions which are contained in cellulose fibers of cotton, flax or the like, and in a bleaching bath, such as iron, calcium, copper and manganese, and therefore, discoloration of the fibers occurs, and the fibers are made brittle.
To eliminate this disadvantage, sodium silicate is frequently used as a bleach stabilizer, but the use of sodium silicate is disadvantageous in that water-insoluble salts of calcium and magnesium, i.e., silicate scales, are formed, and these insoluble salts adhere to and are deposited on a bleached textile and a bleaching apparatus to cause a silicate scale problem.
Bleach stabilizers other than sodium silicate include polyphosphoric acid salts such as sodium tripolyphosphate, and aminocarboxylate organic chelating agents such as ethylenediamine-tetraacetic acid (EDTA) and diethylenetriamine-pentaacetic acid (DTPA). These bleach stabilizers do not cause a silicate scale problem, however, at a pH of 10 to 14, the chelating capacity is reduced. Moreover, these bleach stabilizers are insolubilized in the presence of an excessive amounts of hardness ions.
Heavy metal ions also cause problems in the desizing, scouring, mercerising, and dyeing processes of textiles by complexing with hydroxyl groups to form insoluble salts. The insoluble salts deposit on textiles and equipment causing scale problems and blemishes on textiles.
The invention comprises a processing aid for use in a textile manufacturing or treating process, said processing aid comprises a polyether hydroxycarboxylate copolymer having the structure 
wherein M+ is a cation wherein M is independently selected from the group consisting of hydrogen, ammonia, alkali metals, alkaline earth metals, zinc, copper, organic amines, amino acids, and amino saccharides; R1 is the residue of an ethylenically unsaturated comonomer having at least one functional group which is selected from the group consisting of carboxylic acid, sulfonic acid and phosphonic acid; R2 and R3 are independently selected from the group consisting of hydrogen, and a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms; n is from about 2 to about 100; x1 and x2 are independently 0 or 1; a is from 0 to 100 mole percent; and b is from 100 to 0 mole percent, provided that (a +b) is 100 mole percent,
wherein said processing aid is present in an amount of from about 0.001 to about 50 weight percent, based on the weight of the solution or dispersion used in the textile process.
Another aspect of the invention is an improved bleaching process for preparing woven textiles comprising sizing fibers to be woven in the presence of from about 0.01 to about 10 weight percent of the polyether hydroxycarboxylate copolymer.
An additional aspect of the invention is an improved desizing process for textiles comprising desizing woven textile material in the presence of an alkaline substance and from about 0.001 to about 50 weight percent of the polyether hydroxycarboxylate copolymer.
A further aspect of the invention is an improved scouring process for textiles comprising scouring textiles in the presence of from about 0.001 to about 50 weight percent of the polyether hydroxycarboxylate copolymer.
The polyether hydroxycarboxylate copolymer functions as a processing aid and complexes heavy metal ions in the manufacturing or treating of textiles. For example, the polyether hydroxycarboxylate copolymers help stabilize hydrogen peroxide in the bleaching process, reduce scale and prevent deposition of heavy metal ions such as iron, calcium and magnesium during the scouring, desizing, mercerising, and bleaching processes. In addition, the polyether hydroxycarboxylate copolymers prevent redeposition of particulate soils onto the textiles.
Furthermore, in the dyeing process, the polyether hydroxycarboxylate copolymers disperse direct and dispersed dyes, and suspend unfixed dyes, and thus, provide a consistent and level dyeing of textiles. An additional advantage is that the polyether hydroxycarboxylate copolymers complex salts, such as calcium, magnesium and iron salts, during the dyeing process which prevents the salts from depositing on the textiles and causing blemishes, or precipitating the dyes out of solution which reduces the efficiency of the dyes.
This invention provides a processing aid for use in a textile manufacturing or treating process. Such textile manufacturing and treating processes include desizing, scouring, mercerising, bleaching, and dyeing processes. As used herein, these terms have the following meanings:
(1) xe2x80x9cDesizingxe2x80x9d process is essentially a part of the scouring process, and rapid removal of size is important especially in continuous preparation processes. Desizing of sized fabrics is commonly carried out using water washing at varying temperatures or with enzymes. Desizing can also be carried out effectively with alkaline, preferably caustic solutions, and those alkaline solutions can be very dilute.
(2) xe2x80x9cScouringxe2x80x9d process involves removing or reducing the level of fats, waxes, oils, dirt, and so forth on a textile. Apart from the aesthetic benefits of clean fabric, the major reason for scouring is to improve the extent and uniformity of absorbency for subsequent processes, especially dyeing. Scouring generally takes place using mild alkalinity and surfactants as wetting agents, such as alkylbenzenesulfonate and alkylphenol ethoxylates. It is noted that scouring is particularly important with natural fibers which contain much more extraneous matter than synthetic fibers. For example, cotton, requires high alkalinity scouring, which swells the fibers, allowing access to the lumen and removing soil from the surface.
(3) xe2x80x9cBleachingxe2x80x9d process involves bleaching of the various types of textiles with a peroxide bleaching compound. Suitable peroxide compounds are water soluble peroxides, particularly alkali metal peroxides, preferably sodium peroxide, and hydrogen peroxide, the latter being particularly preferred. The peroxide bleaching is carried out in an alkaline medium. To achieve the alkaline conditions, it is advantageous to use an alkali metal hydroxide, preferably potassium or sodium hydroxide.
(4) xe2x80x9cMercerisingxe2x80x9d process is used to swell cotton fibers in order to increase their lustre, strength, and dyeability. Generally, a cold solution of sodium hydroxide is used, however, hot mercerising techniques and the use of acids, such as cresylic acid along with a cosolvent, may also be employed.
(5) xe2x80x9cDyeingxe2x80x9d process involves the application of a solution or a dispersion of a dye to a textile followed by some type of fixation process. The dye solution or dispersion is almost always an aqueous medium, and a major objective of the fixation step is to ensure that the colored textile exhibits satisfactory fastness to subsequent treatment in aqueous wash liquors.
Suitable textiles to be treated with the polyether hydroxycarboxylate copolymers of the invention are, for example, cotton, polyacrylics, polyamides, polyesters, polyolefins, rayons, wool, linen, jute, ramie, hemp, sisal, regenerated cellulosic fibers such as rayon or cellulose acetate, and blends thereof. The textiles can be in a variety of forms, for example, yarn, tops, woven, knitted, plush and carpets.
The processing aid of the invention comprises a polyether hydroxycarboxylate copolymer having the structure 
wherein M+ is a cation wherein M is independently selected from the group consisting of hydrogen, ammonia, alkali metals, alkaline earth metals, zinc, copper, organic amines, amino acids, and amino saccharides. Preferably the cation is independently hydrogen or sodium.
In the above structure for the polyether hydroxycarboxylate copolymer, R2 and R3 are independently selected from the group consisting of hydrogen, an alkyl group having 1 to 4 carbon atoms, a substituted alkyl group having 1 to 4 carbon atoms, and combinations thereof. When R2 and R3 are hydrogen, the monomer used to prepare the repeating unit (a) is maleic acid. However, methylmaleic acid (citraconic acid) and other substituted cisbutenedioic acids can be substituted for maleic acid.
In the above structure for the polyether hydroxycarboxylate copolymer, R1 is the residue of an ethylenically unsaturated comonomer having at least one functional group which is selected from the group consisting of carboxylic acid, sulfonic acid and phosphonic acid. Suitable ethylenically unsaturated comonomers having a carboxylic acid functional group are acrylic acid, methacrylic acid, itaconic acid, ethacrylic acid, alpha-chloro-acrylic acid, alpha cyano acrylic acid, crotonic acid, alpha phenyl acrylic acid, beta acryloxy propionic acid, sorbic acid, angelic acid, cinnamic acid, glutaconic acid, 2-acrylamido glycolic acid, and tricarboxyethylene. A preferred ethylenically unsaturated comonomer having carboxylic acid functional groups is itaconic acid.
Suitable ethylenically unsaturated comonomers having a sulfonic acid or phosphonic acid functional group are vinyl sulfonic acid, sodium methallyl sulfonate, 2-acrylamido 2 methyl propane sulfonic acid, allyloxybenzene sulfonic acid, and vinyl phosphonic acid. Preferred ethylenically unsaturated comonomers having a sulfonic acid or phosphonic acid functional group are vinyl sulfonic acid and vinyl phosphonic acid.
Thus, the polyether hydroxycarboxylate copolymer is prepared from (a) and (b) repeating units. The (a) repeat units are derived from either maleic acid, methylmaleic acid, or other substituted cisbutenedioic acids. The (b) repeat units are derived from an ethylenically unsaturated comonomer having at least one functional group which is selected from the group consisting of carboxylic acid, sulfonic acid and phosphonic acid.
In the above structure for the polyether hydroxycarboxylate copolymer, n is from about 2 to about 100. Preferably n is from about 2 to about 20, more preferably from 2 to 10. The letters X1 and X2 are independently 0 or 1. The letter a is from 0 to 100 mole percent, preferably to 100 mole percent. The letter b is from 0 to 100 mole percent, preferably 0 to 80 mole percent, provided that (a +b) is 100 mole percent.
A preferred process for preparing the polyether hydroxycarboxylate copolymers involves mixing the monomer(s) responsible for repeating unit (a) and comonomer(s) responsible for repeating unit (b) together with water to form a mixture. The monomer(s) and comonomer(s) in the mixture are neutralized or partially neutralized using a base. A preferred base is sodium hydroxide. Preferably, at least 60% of the total acid groups are neutralized.
The next step involves epoxidation of the ethylenically unsaturated double bonds present in the monomer(s) and comonomer(s) to form a mixture of epoxides. Methods for epoxidation are well known in the art, such as described by G. B. Payne and P. H. Williams in the Journal of Organic Chemistry, vol. 24, p. 54 (1959) which is incorporated herein by reference. For example, a combination of an oxidizer such as hydrogen peroxide and a catalyst such as sodium tungstate may be used. It is within the scope of the invention that not all of the ethylenically unsaturated double bonds present in the monomer(s) and comonomer(s) are epoxidized. Optionally, the neutralization step or partial neutralization may be carried out after forming the epoxides.
The epoxides are polymerized by means of an anionic polymerization process to form the polyether hydroxycarboxylate copolymer product. Any monomer(s) and/or comonomer(s) which have not been epoxidized may be polymerized such that either X1 , X2 , or both are equal to 0 in the polyether hydroxycarboxylate copolymer product. Preferably, X1 and X2 are equal to 1 in the polyether hydroxycarboxylate copolymer. The polymerization is conducted in the presence of calcium hydroxide or other alkaline calcium salts. A description of a method for polymerizing an epoxide derived from maleic acid is included in U.S. Pat. No. 4,654,159 which is incorporated herein by reference.
The polyether hydroxycarboxylate copolymer product containing sodium and calcium salts can be used in the form of an aqueous solution.
Alternatively, the sodium or calcium salts may be replaced by means of ion exchange by an alkali metal, such as sodium, or by ammonium, substituted ammonium, or hydrogen. Optional removal of low molecular weight components (n=1) may be carried out using a suitable process such as vacuum distillation.
In one embodiment of the invention, the process can be represented as follows: 
wherein CH2CHR4 is an ethylenically unsaturated comonomer containing carboxylic acid, phosphonic acid, sulfonic acid group or a combination thereof.
The concentration of the polyether hydroxycarboxylate copolymer in a textile manufacturing or treating process is preferably from about 0.001 to about 50 weight percent, based on the weight of the solution or dispersion used in the textile process. More preferably, the polyether hydroxycarboxylate copolymers are present in an amount of from about 0.1 to about 10 weight percent.
In one embodiment, where the polyether hydroxycarboxylate copolymer is used at the steps of desizing, scouring and bleaching textiles, not only a hydrogen peroxide-stabilized effect but also a high decomposition-promoting effect can be attained, and an abnormal decomposition by metal ions such as iron, copper and calcium ions can be controlled. Furthermore, a good dispersibility is given to decomposition products and a redeposition of decomposition products can be prevented. The polyether hydroxycarboxylate copolymers of the invention have the additional advantage of acting as complexing agents in softening water by complexing the xe2x80x9chardnessxe2x80x9d cations in water. The polyether hydroxycarboxylate copolymers form a soluble complex with calcium and magnesium ions which otherwise can react with soaps and other anionic surfactants and otherwise adversely affect detergency or cleaning of the textiles.
In one embodiment, where the polyether hydroxycarboxylate copolymer is used for the mercerization of cotton or flax, the polyether hydroxycarboxylate copolymer can be incorporated into a mercerizing bath or soaping bath of a yarn mercerizing machine or a knitted or woven fabric mercerizing machine. Since the alkali resistance of the polyether hydroxycarboxylate is good, a decomposition or separation of the polyether hydroxycarboxylate per se does not occur, the deposition of scales on a roll or the like is prevented, and the dispersibility of the bath is improved.
The polyether hydroxycarboxylate copolymer functions as a processing aid and complexes heavy metal ions in the manufacturing or treating of textiles. For example, the polyether hydroxycarboxylate copolymers help stabilize hydrogen peroxide in the bleaching process, reduce scale and prevent deposition of heavy metal ions such as iron, calcium and magnesium during the scouring, desizing, mercerising, and bleaching processes. In addition, the polyether hydroxycarboxylate copolymers prevent redeposition of particulate soils onto the textiles.
Furthermore, in the dyeing process, the polyether hydroxycarboxylate copolymers disperse direct and dispersed dyes, and suspend unfixed dyes, and thus, provide a consistent and level dyeing of textiles. An additional advantage is that the polyether hydroxycarboxylate copolymers complex salts, such as calcium, magnesium and iron salts, during the dyeing process which prevents the salts from depositing on the textiles and causing blemishes, or precipitating the dyes out of solution which reduces the efficiency of the dyes.
The following nonlimiting examples illustrate further aspects of the invention.